Before Trainspotting was a film that launched half a dozen careers, there was a stage adaptation by Harry Gibson. This is the version now given an immersive revival at the King's Head, to commemorate 21 years since the publication of Irvine Welsh's original novel. Much of the bench seating has been removed in Sandy Hale's set design, which crams the audience around the action for Greg Esplin and Adam Spreadbury-Maher's production. Renton (Gavin Ross) narrates the story of his life as a heroin addict in late '80s-early '90s Edinburgh, surrounded by friends who are mostly fellow junkies or, if they're not, are somehow even more fucked up, like the psychotically violent Begbie (Chris Dennis.) If you're somehow unfamiliar with Trainspotting, you might have missed the fact that it's a black comedy, an element that's much in evidence in the play's early scenes, but which gradually subsides as the consequences of addiction become impossible to ignore any longer.